How Debian managed the systemd transition

Oh, I agree it would be bad by modern standards -- however, it was quite clearly capable of scaling to the point of handling graphics data with no more kernel support than that. To get back to the original point: unless you think D-Bus is not just going to be asked to handle graphics data but the full graphics flow of a 3D game I think the volume of data involved in graphics should not serve as an argument for needing kernel support just to handle that.